1. Field of the Invention
The present invention relates to duplex image reading apparatus for reading images on two sides of an original transported by original transporting means.
2. Description of Related Art
Among conventional duplex image reading apparatus is one proposed in such structure that two image reading devices are arranged in a fixed state on respective sides of a bent transportation path, as described in Japanese Patent Application Laid-Open No. 2000-115452.
There is another apparatus proposed in such structure that two image reading devices are arranged at positions almost opposite to each other, one image reading device is fixed, and the other image reading device is urged against the fixed image reading device, as described in Japanese Patent Application Laid-Open No. 10-190938.
In the former conventional example (Japanese Patent Application Laid-Open No. 2000-115452) described above, however, the positional relation between the two image reading devices was greatly associated with the transportation performance of an original and there was the drawback that, particularly, when two image reading surfaces were not parallel but inclined, the original was not smoothly transported, so as to cause an original jam. In order to avoid it, it was necessary to apply severe dimensional accuracy to components and provide means of provision of an adjusting mechanism, which was the cause of cost increase.
In the foregoing latter conventional example (Japanese Patent Application Laid-Open No. 10-190938), since the apparatus was applied to the image reading apparatus, such as facsimile machines and image scanners, the structure did not allow use of general-purpose image reading devices typified by contact image sensors. For this reason, it was necessary to fabricate dedicated image reading devices, but it must raise the cost considerably.